CN111247727B

CN111247727B - Self-contained brushless motor and brushless controller

Info

Publication number: CN111247727B
Application number: CN201880050017.4A
Authority: CN
Inventors: 乔纳森·芬克豪泽; 王伟; 朱昊
Original assignee: Yuyao Actuator Electric Motor Co ltd
Current assignee: Yuyao Actuator Electric Motor Co ltd
Priority date: 2017-05-27
Filing date: 2018-05-25
Publication date: 2021-10-08
Anticipated expiration: 2038-05-25
Also published as: WO2018222523A1; CN111247727A; US20180342934A1; EP3631953B1; EP3631953A4; EP3631953A1; US10840776B2

Abstract

A brushless DC motor assembly includes a housing having a first end and a second end and a stator disposed in the housing. The assembly also includes a rotor subassembly disposed in the stator, the rotor subassembly having a shaft with a first end proximate the first end of the housing and a second end proximate the second end of the housing. The assembly also includes a controller disposed in the housing, the controller configured to control rotation of the shaft. The first end of the shaft is configured to provide a rotational output.

Description

Self-contained brushless motor and brushless controller

Cross Reference to Related Applications

The present application is incorporated herein in its entirety by reference to the priority benefit of U.S. patent application No. 15/710,045 filed 2017, 9, 20, 119 and by reference to the priority benefit of international application No. PCT/CN2017/086314 filed 2017, 5, 27, 2017, 35 u.s.c. § 119.

Background

The present application relates generally to the field of brushless motors and, more particularly, to motors having a controller disposed within a motor housing.

Power tools (e.g., hand held tools, lawn garden tools, etc.) are typically powered by a permanent magnet direct current ("PMDC") motor. Brushes in a PMDC motor physically engage a commutator, thereby generating friction between the brushes and the commutator. This friction can lead to operating noise, brush wear, and elevated operating temperatures, limiting the useful life of the PMDC motor.

SUMMARY

One embodiment relates to a brushless dc motor assembly including a housing having a first end and a second end and a stator disposed in the housing. The assembly also includes a rotor subassembly disposed in the stator, the rotor subassembly having a shaft with a first end proximate the first end of the housing and a second end proximate the second end of the housing. The assembly also includes a controller disposed in the housing, the controller configured to control rotation of the shaft. The first end of the shaft is configured to provide a rotational output.

Another embodiment relates to an electrical device that includes a driven member and a brushless dc motor assembly. The assembly includes a housing having a first end and a second end and a stator disposed in the housing. The assembly also includes a rotor subassembly disposed in the stator, the rotor subassembly having a shaft with a first end proximate the first end of the housing and a second end proximate the second end of the housing. The assembly also includes a controller disposed in the housing, the controller configured to control rotation of the shaft. The first end of the shaft is coupled to the driven member, and the shaft is configured to rotate the driven member.

Brief Description of Drawings

Fig. 1 is an exploded view of an electric machine according to an exemplary embodiment.

Fig. 2 is a cross-sectional view of the motor of fig. 1.

Fig. 3 is a rear perspective view of the motor of fig. 1 with the cover removed.

Detailed Description

Various embodiments are described below. It should be noted that the specific embodiments are not intended as an exhaustive description or as a limitation on the broader aspects discussed herein. An aspect described in connection with a particular embodiment is not necessarily limited to that embodiment and may be practiced in any other embodiments.

The use of the terms "a" and "an" and "the" and similar referents in the context of describing features (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Unless otherwise indicated herein, numerical ranges are intended merely as shorthand methods of referring individually to each separate value falling within the range, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate embodiments and does not pose a limitation on the scope of the claims unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed feature as essential.

To reduce friction in the motor, a brushless direct current (BLDC) motor may be used instead of the PMDC motor. In a BLDC motor, current flows through windings in the stator, creating a magnetic field to interact with permanent magnets on the rotor. The rotor and the stator are physically separated, so that the BLDC can operate without any brush, thereby reducing friction of the BLDC motor with respect to the PMDC motor. However, in contrast to PMDC motors, BLDC motors require a controller to operate. In conventional BLDC motors, the controller is located external to the motor (e.g., in the handle or pedal of the tool).

As will be apparent from the following, it may be advantageous to provide a BLDC motor having a controller disposed within a motor housing. For example, by positioning the controller within the housing, the motor may be fully assembled prior to installation in the electrical equipment (e.g., power tool, etc.), thereby reducing the cost and complexity of installing the motor in the electrical equipment to rotate the driven member. For power tools, a motor may be coupled to a chuck as a driven member (e.g., for drills, lathes, etc.). Similarly, the motor may drive a socket to mount a lug (lug) on a car or truck. Further, structures in the housing may help cool the controller. For example, the housing may include fans and other structures as heat sinks.

Referring to fig. 1 and 2, a BLDC motor assembly 10 is shown in accordance with an illustrative embodiment. The assembly 10 includes a stator 12 having a first (e.g., front) end 14 and an opposite second (e.g., rear) end 16. The electromagnetic wire forms a plurality of windings 18 around the stator 12. The winding 18 is configured to receive a current (e.g., direct current) therethrough, generating a magnetic field. The stator 12 defines a stator bore 20 extending from the first end 14 to the second end 16, and the stator bore 20 is configured to receive a rotor subassembly 22 disposed therein.

The rotor subassembly 22 includes a magnet ring 24 having a first (e.g., front) end 26 and an opposite second (e.g., rear) end 28. The magnetic ring 24 defines a magnetic ring bore 30 extending from the first end 26 to the second end. The magnetic ring 24 is formed of a permanent magnet configured to magnetically interact with the magnetic field generated by the windings 18. A sensor magnet 32 is disposed adjacent the second end 28 of the magnet ring 24 and defines a sensor magnet bore 34 extending therethrough. The sensor magnet 32 includes at least two pairs of north and south poles. For example, a first north-south pole pair defines a first magnetic axis (e.g., coplanar with the sensor magnet 32), and a second north-south pole pair defines a second magnetic axis (e.g., coplanar with the sensor magnet 32) that intersects (e.g., perpendicular, orthogonal) the first magnetic axis. According to other illustrative embodiments, the sensor magnet 32 may define more or fewer north-south pole pairs. As shown in fig. 2, the sensor magnet 32 is disposed proximate to the controller 78 such that the magnetic poles in the sensor magnet 32 magnetically interact with the hall sensor on the controller 78. The hall sensor toggles between an on position and an off position based on the orientation of the magnetic poles, thereby measuring the rotational speed of the rotor subassembly 22. Fig. 1 and 2 show the sensor magnet 32 formed separately from the magnet ring, and according to other illustrative embodiments, the second end 28 of the magnet ring 24 may be magnetized with a desired pole configuration to magnetically interact with the hall sensor.

The rotor subassembly 22 also includes a shaft 38 (e.g., a rotor) disposed in the magnetic ring bore 30 and the sensor magnet bore 34. The shaft 38 has a generally annular (e.g., cylindrical) shape and defines a first (e.g., front, output) end 40 and a second (e.g., rear) end 42. The first end 40 of the shaft 38 is configured to provide a rotational output from the assembly 10. The shaft 38 has an axial length L extending between first and second ends 40, 42₁，L₁Is substantially greater than a stator length L extending between the first and second ends 14, 16 of the stator 12₂. In this configuration, at least one of the ends 40, 42 of the shaft 38 extends axially outward from the stator 12 when the rotor subassembly 22 is disposed in the stator 12. As shown in fig. 2, both ends 40, 42 may extend axially outward from the stator 12. Further, the sensor magnet 32 and the spacer 36 are disposed proximate the second end 16 of the stator 12 and axially outward from the second end 16 of the stator 12.

Still referring to fig. 1 and 2, a spacer 36 may be disposed between the magnet ring 24 and the sensor magnet 32 to space the sensor magnet 32 from the magnet ring 24. The shaft 38 is coupled to the sensor magnet 32 and is rotationally fixed relative to the sensor magnet 32 such that when the magnet ring 24 rotates the sensor magnet 32, the shaft 38 rotates at substantially the same angular velocity as each of the magnet ring 24 and the sensor magnet 32. As shown in fig. 2, a sleeve 44 is disposed between the sensor magnet 32 and the shaft 38, directly on the shaft 38 near the second end 42, and is configured to maintain a fixed rotational orientation between the sensor magnet 32 and the shaft 38. For example, the sleeve 44 may be formed of a compressible material configured to frictionally engage the shaft 38. For example, the sleeve 44 may be a brass ring that is press fit onto the shaft 38 such that the sleeve 44 is rotationally fixed relative to the shaft 38. The sensor magnet bore 34 may define a complementary feature to the sleeve 44, or may frictionally engage the sleeve (e.g., by being press-fit onto the sleeve 44 or over-molded onto the sleeve 44) such that the sensor magnet 32 is rotationally fixed relative to the sleeve 44. According to another exemplary embodiment, one of the shaft 38 or the sleeve 44 defines a slot and the other of the shaft 38 or the sleeve 44 defines a key configured to be received in the slot. The sensor magnet 32 may also be rotationally fixed to the shaft 38 in other ways.

Still referring to fig. 1 and 2, the rotor subassembly 22 also includes a fan 46. The fan 46 includes: a hub 48 defining a fan aperture 50 extending therefrom; and a plurality of vanes 52 extending radially outward from the hub 48. The fan 46 is disposed near or on the first end 26 of the magnet ring 24, and the fan aperture 50 is configured to receive the shaft 38 extending therethrough. The fan 46 is coupled to at least one of the magnet ring 24 or the shaft 38 such that the fan 46 is rotationally fixed relative to the shaft 38. As the rotational speed of the shaft 38 increases in the stator 12, the rotational speed of the fan 46 also increases, thereby increasing the airflow in the assembly 10 to cool the assembly 10.

The assembly 10 also includes a housing 54 (e.g., a cover, shell, etc.) defining a first (e.g., front) end 56 and a second (e.g., rear) end 58. The housing 54 is substantially annular (e.g., cylindrical) defining a specific stator outer diameter D₂Large inner diameter D of casing₁(e.g., at about 30mm to 70 mm) such that the stator 12 is configured to be received within the housing 54. Similarly, the outer diameter D of the fan₃Smaller than the inner diameter D of the housing₁Such that the fan 46 and rotor subassembly 22 are more generally configured to be housed within the housing 54. A first plurality of (e.g., intake) openings 60 are provided in the housing 54 proximate the first end 56, and a second plurality of (e.g., exhaust) openings 62 are provided in the housing 54 proximate the second end 58. The vanes 52 are disposed proximate the first opening 60 and are configured to draw air into the housing through the first opening 60 and toward the second opening 62 during operation of the assembly 10The interior of the body 54 to cool the components within the housing 54. According to other illustrative embodiments, the first opening 60 and/or the second opening 62 may be configured to provide a passage for wiring to extend into the housing 54.

The first retainer 15 is configured to engage the first end 14 of the stator 12 and the second retainer 17 is configured to engage the second end 16 of the stator 12. The first retainer 15 and the second retainer 17 are disposed between and engaged with the stator 12 and the housing 54 so that the stator 12 is not directly engaged with the housing 54. The first and second retainers 15, 17 are formed of a substantially electrically non-conductive material and are configured to electrically insulate the stator 12 from the housing 54.

A first (e.g., front) cover 64 is disposed on the first end 56 of the housing 54 and defines a first cover aperture 66, the first cover aperture 66 being configured to receive the first end 40 of the shaft 38 therethrough. Similarly, a second (e.g., rear) cover 68 is disposed on the second end 58 of the housing 54 and defines a second cover aperture 70, the second cover aperture 70 being configured to receive the second end 42 of the shaft 38 therethrough. According to another illustrative embodiment, one of the first and second covers 64, 68 may be substantially solid (e.g., without the bores 66, 70 for receiving the shaft 38). A first ball bearing 72 is annularly disposed about the shaft 38 proximate the first end 40 and engages the bore 66 of the first cover 64 such that the shaft 38 is supported by the first cover 64. Similarly, a second ball bearing 74 is annularly disposed about the shaft 38 adjacent the second end 42 and engages the aperture 70 of the second cover 68 such that the shaft 38 is also supported by the second cover 68. As shown in fig. 1 and 2, at least one washer 76 (e.g., spacer, washer, etc.) may be disposed between the rotor subassembly 22 and the first ball bearing 72 and/or between the rotor subassembly 22 and the second ball bearing 74. In various illustrative embodiments, the first and second covers 64, 68 may be fastened (e.g., by rivets, screws, bolts, etc.) to the housing 54, or may be otherwise connected (e.g., welded) to the housing 54.

Referring now generally to fig. 1-3, a controller 78 is shown in accordance with an illustrative embodiment. The controller 78 may be connected to the stator with screws and/or plastic clips extending from the stator to the controller 78.The controller 78 is configured to control the operation of the assembly 10 by controlling the current flowing through the windings 18, which in turn controls the rotational speed of the rotor subassembly 22 in the stator 12. For example, the controller 78 is configured to control the rotation of the shaft 38, and thus the rotational output of the shaft 38 from the assembly 10. The controller 78 is disposed within the housing 54 proximate the second end 58, between the second end 16 of the stator 12 and the second cover 68. For example, the controller 78 is substantially circular (e.g., ring, disk shaped) defining a controller outer diameter D₄The outer diameter D₄Less than the inner diameter D of the housing₁Such that the controller 78 may be completely enclosed within the housing 54 and not located outside of the housing 54. Controller outer diameter D₄Or the inner diameter D of the housing₁May be between about 30mm and 70 mm. The size of conventional controllers is not small enough to fit within a housing inner diameter D of less than or equal to 70 millimeters₁While still accommodating all of the components required to operate the assembly 10.

The controller 78 defines a controller bore 80 and is configured to receive the second end 42 of the shaft 38 therethrough. The controller aperture 80 enables the controller 78 to be disposed within the housing 54 without interfering with the placement and movement of the shaft 38. Fig. 1 and 3 show that the controller 78 is substantially circular, and according to other illustrative embodiments, the controller 78 may include other shapes and sizes such that the controller 78 may be completely enclosed within the assembly 10 with the second end 42 of the shaft 38 extending through the controller aperture 80.

Referring to fig. 1 and 2, the assembly 10 includes a conductive (e.g., first) ring 82 disposed between the controller 78 and the second cover 68. For example, opposing surfaces of the conductive ring 82 may directly engage the controller 78 and the second cover 68, and thus, the conductive ring 82 is configured to conduct heat from the controller 78 and to transfer heat to the second cover 68. In this configuration, the second cover 68 may be formed of aluminum and act as a heat sink so that the controller 78 does not overheat during operation. The heat transfer between the controller 78 and the second cover 68 also enables the controller 78 to be enclosed within the housing 54 without damaging the controller 78. According to an illustrative embodiment, the conductive ring 82 may be formed from a high pressure and high temperature resistant material. Illustrative high pressure and high temperature resistant materials include, but are not limited to, silicone and other suitable materials configured to conduct heat and electrically insulate the controller 78 directly from the second cover 68 and indirectly from the housing 54. Conductive ring 82 may further be flexible (e.g., compressible) and configured to absorb vibrations applied to housing 54 rather than transmit vibrations to controller 78. By physically isolating the controller 78 from the additional stresses, the likelihood of loosening of components on the controller 78 is reduced.

Referring to fig. 1 and 3, the assembly 10 includes an insulating (e.g., second) ring 84 disposed between the controller 78 and the housing 54. For example, the insulating ring 84 may be formed from insulating paper disposed annularly (e.g., radially) around the controller 78 and configured to electrically insulate the controller 78 from the housing 54. For example, the insulating paper may be formed of a material resistant to high pressure and high temperature. Although fig. 1-3 illustrate the assembly 10 having separate conductive and insulating rings 82, 84 configured to electrically isolate the controller 78 from the housing 54, according to other illustrative embodiments, the rings 82, 84 may be formed as a single ring having insulating properties, or the assembly 10 may include additional rings configured to electrically isolate the controller 78.

Although fig. 1-3 show the controller 78 disposed between the stator 12 and the second cover 68, according to another illustrative embodiment, the controller 78 may be disposed between the stator 12 and the first cover 64 such that the first end 40 of the shaft 38 extends through the controller aperture 80. In such a configuration, the fan 46 may be disposed between the controller 78 and the first cover 64, between the controller 78 and the stator 12, or between the stator 12 and the second cover 68. When the fan 46 is disposed adjacent the second cover 68, the blades 52 are configured to draw air into the housing 54 through the second opening 62. The conductive ring 82 may be disposed between the controller 78 and the first cover 64, and the insulating ring 84 may be disposed annularly about the controller 78 as described above. Further, the first cover 64 may function as a heat sink.

The controller 78 includes a printed circuit board assembly ("PCBA"). The PCBA includes MOSFETs, MCUs and hall effect sensors and is configured to communicate with and control a DC voltage system (e.g., a battery), lights for illumination (e.g., LEDs), a speed controller and/or switches. For example, the hall effect sensor is disposed on the same PCBA as at least one of the MOSFET or MCU, rather than on a separate board for the hall effect sensor only. This configuration reduces the size of the PCBA that is installed in the assembly 10 as part of the controller 78. Although in the illustrative embodiment, the controller 78 is described as having certain components (e.g., sensors), it should be understood that in other embodiments, the controller 78 may have more or fewer components, or may have different components than those specifically described so far. The controller 78 may be formed from more than one layer such that each layer is configured to fit within the housing 54. For example, the controller 78 may include five layers (although more or fewer layers may be included). The hall effect sensors disposed in the layer closest to the sensor magnet 32 and the controller 78 are spaced approximately 0.5mm from the sensor magnet 32 to ensure proper magnetic interaction therebetween. The hall effect sensor may be disposed on a first side of the layer of the controller 78 that is closest to the sensor magnet 32, while the MOSFET may be disposed on an opposite second side of the layer of the controller 78 such that the MOSFET faces the second cover 68, which acts as a heat sink for the MOSFET. The controller 78 may include about 6 to 12 MOSFETs. For example, the MOSFETs may be provided in multiples of six and configured to transfer power from the power supply to the stator 12 or other portion of the assembly 10. Specifically, the assembly 10 may be configured to receive power and operate in the range of approximately 3.6-60V or, more specifically, between approximately 50-60V. In the above configuration, the assembly 10 may be provided as a fully integrated BLDC motor unit without any additional external controller for operation. Advantageously, by locating all of the components within the housing 54, the assembly 10 is much easier to install in a variety of tools or automobiles.

As used herein, the terms "about," "significantly," "largely," and the like are intended to have a broad meaning consistent with the accepted common usage by those of ordinary skill in the art. It will be understood by those skilled in the art that these terms are intended to describe certain features described and claimed, and not to limit the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the described and claimed subject matter are considered within the scope of the disclosure as recited in the appended claims.

It should be noted that the term "illustrative," as used herein to describe various embodiments, is intended to indicate that such embodiments are possible examples, representations, and/or illustrations of possible implementations (and that the term is not intended to represent that such embodiments are necessarily the best or highest-ranking examples).

As used herein, the terms "coupled," "connected," and the like refer to two members being connected to each other either directly or indirectly. Such a connection may be fixed (e.g., permanent) or movable (e.g., removable or releasable). Such joining may be achieved with the two members, or with the two members and any additional intermediate members being integrally formed as a single unitary body with one another, or with the two members or the two members and any additional intermediate members being attached to one another.

References herein to the position of features (e.g., "top," "bottom," "above," "below," etc.) are merely used to describe the orientation of the various features in the drawings. It should be noted that the orientation of the various elements may differ according to other illustrative embodiments, and such variations are intended to be covered by the present disclosure.

It should be understood that although the present invention has been described in relation to its preferred embodiments, various other embodiments and modifications may occur to those skilled in the art, which are within the spirit and scope of the invention and these other embodiments and modifications are intended to be covered by the corresponding claims. Those skilled in the art will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, mounting arrangements, use of materials, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. For example, the order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various illustrative embodiments without departing from the scope of the present disclosure.

The embodiments illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations, not specifically disclosed herein. Thus, for example, the terms "comprising," "including," and the like are to be construed broadly and without limitation. Additionally, the terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the claimed technology. In addition, the phrase "consisting essentially of … …" will be understood to include those elements specifically recited and those additional elements that do not materially affect the basic and novel characteristics of the claimed technology. The phrase "consisting of" does not include any elements not specified.

In addition, where features or aspects of the disclosure are described in terms of markush groups, those skilled in the art will recognize that the disclosure also thereby describes any individual member or subgroup of members of the markush group.

As will be understood by those skilled in the art, for any and all purposes, particularly in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily identified as fully descriptive and the same range can be broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein may be readily broken down into a lower third, a middle third, and an upper third, among others. As those skilled in the art will also appreciate, all language (e.g., "at most," "at least," "greater than," and "less than," etc.) includes the number recited and refers to a range, which range can then be subdivided into sub-ranges as described above. Finally, as will be understood by those of skill in the art, a range includes each individual member.

All publications, patent applications, issued patents, and other documents mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, issued patent, or other document was specifically and individually indicated to be incorporated by reference in its entirety. If a definition contained in a text incorporated by reference is left to the definition herein, the definition herein controls.

Other embodiments are set forth in the following claims.

Claims

1. A brushless dc motor assembly (10), comprising:

a housing (54) having a first end (56) and a second end (58);

a stator (12) disposed in the housing (54);

a rotor subassembly (22) disposed in the stator (12), the rotor subassembly (22) including a shaft (38) having a first end (40) proximate a first end (56) of the housing and a second end (42) proximate a second end (58) of the housing;

a first cover (64) disposed on the first end (56) of the housing;

a second cover (68) disposed on the second end (58) of the housing, the housing (54) being surrounded by the first cover (64) and the second cover (68); wherein the content of the first and second substances,

a housing (54) comprising a plurality of air inlet openings (60) proximate the first end (56) and a plurality of air outlet openings (62) proximate the second end (58), wherein the housing is generally tubular between the first end (56) and the second end (58) thereof, and wherein the housing has an inner diameter between 30mm and 70 mm;

a controller (78) disposed in the housing (54), the controller (78) being located between the second cover (68) and the stator (12) and the controller (78) being directly mechanically connected to the stator (12), the controller (78) being configured to control rotation of the shaft (38), wherein an outer diameter of the controller (78) is less than an inner diameter of the housing (54), the controller (78) comprising;

a printed circuit board assembly, or PCBA, having a first side and an opposite second side, the second side facing a second cover (68), the PCBA including a plurality of electrical components including: a microcontroller unit, i.e. MCU; a plurality of Hall effect sensors; and at least 6 metal-oxide-semiconductor field-effect transistors (MOSFETs), wherein at least one of the plurality of Hall effect sensors is disposed on the first side and at least one of the MOSFETs is disposed on the second side, the PCBA configured to communicate with and control at least one of a DC battery, a speed controller, and a switch;

a fan (46) rotationally fixed relative to the shaft (38), the fan (46) being disposed between the first cover (64) and the stator (12) and proximate the intake opening (60), the fan (46) being configured to draw air into the interior of the housing (54) through the intake opening (60) and toward the exhaust opening (62) to cool the electrical components during operation; and

a conductive ring (82) disposed between the controller (78) and the second cover (68); the conductive ring (82) is configured to transfer heat from the controller (78) to the second cover (68); and electrically insulating the controller (78) from the second cover (68), the conductive ring (82) being formed of a high pressure and high temperature resistant material;

wherein the second cap (68) is configured to act as a heat sink to extract heat from the MOSFET;

wherein the controller (78) defines a controller bore (80), the controller bore (80) configured to receive the shaft (38) therethrough; and

wherein the first end (40) of the shaft (38) is configured to provide a rotational output.

2. The assembly of claim 1, wherein the rotor subassembly (22) further comprises: a brass sleeve (44) press fit adjacent the second end (42) of the shaft (38); and a sensor magnet (32) overmolded on the brass sleeve (44);

wherein the sensor magnet (32) is rotationally fixed relative to the shaft (38); and is

Wherein the sensor magnet (32) is configured to magnetically interact with a Hall effect sensor on the controller (78) to measure a rotational speed of the rotor subassembly (22).

3. The assembly of claim 1, further comprising an insulating ring (84) disposed between the controller (78) and the housing (54), the insulating ring (84) configured to electrically insulate the controller (78) from the housing (54).

4. The assembly of claim 3, wherein the insulating ring (84) is formed of a high pressure and high temperature resistant material.

5. The brushless dc motor assembly according to claim 1, wherein the controller (78) comprises five layers.

6. The brushless DC motor assembly according to claim 1,

wherein the fan (46) directs airflow toward a first side of the PCBA to cool electrical components located on the first side, and wherein the conductive ring (82) and the second cover (68) together cool electrical components located on a second side of the PCBA.

7. The brushless DC motor assembly of claim 1, wherein at least one of the MOSFETs is disposed on a first side of the PCBA.

8. The brushless DC motor assembly of claim 1, wherein opposing surfaces of the conductive ring (82) directly engage the controller (78) and the second cover (68).

9. The brushless dc motor assembly according to claim 1, wherein the exhaust opening (62) is disposed between the intake opening (60) and the controller.

10. An electrical device, comprising:

a driven member;

the brushless DC motor assembly (10) of claim 1,

wherein the first end (40) of the shaft (38) is coupled to the driven member; and is

Wherein the shaft (38) is configured to rotate the driven member.

11. The electrical device of claim 10, wherein the driven member is a chuck or socket.